CN113121064B

CN113121064B - Efficient composite wetland system for reducing rainfall runoff pollutants

Info

Publication number: CN113121064B
Application number: CN202110418701.7A
Authority: CN
Inventors: 崔晓宇; 张朋飞; 彭文启; 骆辉煌; 付意成; 赵进勇
Original assignee: China Institute of Water Resources and Hydropower Research
Current assignee: China Institute of Water Resources and Hydropower Research
Priority date: 2021-04-19
Filing date: 2021-04-19
Publication date: 2022-02-11
Anticipated expiration: 2041-04-19
Also published as: CN113121064A

Abstract

The invention provides a high-efficiency composite wetland system for reducing rainfall runoff pollutants, which comprises a settling area, a surface flow wetland, a deep purification unit and a water collecting well, wherein the settling area is used for settling large-particle impurities such as silt in rainfall runoff so as to reduce the blockage of wetland fillers, the surface flow wetland is in a winding up and down shape, a certain landscape water surface is formed while a hydraulic regulation effect is achieved, organic pollutants in water are removed through submerged plants and the like when rainwater flows, the deep purification unit is used for removing ammonia nitrogen and phosphorus in the water, and the fully purified rainwater is discharged through a gate on the water collecting well; through water level control device control liquid level, rainfall runoff can stay for a long time in the wetland system, reaches the purpose of abundant purification to can adjust the water level of wetland system as required, solve current traditional constructed wetland because of there is not the problem that the water level control function leads to the decontamination effect poor and decontamination efficiency low.

Description

Efficient composite wetland system for reducing rainfall runoff pollutants

Technical Field

The invention relates to the technical field of artificial wetlands, in particular to a high-efficiency composite wetland system for reducing rainfall runoff pollutants.

Background

Generally, water pollution sources are classified into two categories, point source pollution and surface source pollution, which are controlled by different treatment methods. Point source pollution has a definite discharge point (e.g., domestic sewage and industrial wastewater discharged from residential areas or industries), and can be easily collected through a pipe network and discharged into a sewage treatment plant for treatment. The non-point source pollution distribution range is large, pollutants deposited in farmland planting areas, lands, grasslands, forest lands, construction sites, roads and the like are included, particularly in the rainfall period, through the scouring of initial rainwater, the pollutants can enter natural water along with rainwater runoff, and the treatment and control difficulty is large. Common treatment methods for reducing non-point source pollutants comprise constructed wetlands, grass planting ditch filtration, pools, physical filtration equipment (filter tanks, infiltration tanks, porous packages) and the like. The artificial wetland is a non-point source pollution treatment method which is closer to natural purification, has good effect on non-point source pollutant degradation or rainfall runoff control in cities and towns, and pollutants can be purified through filtration and adsorption in wetland fillers, microbial decomposition and aquatic plant absorption. The treatment method utilizes the purification function of a natural ecosystem to remove pollutants and is used as a treatment facility for treating non-point source pollutants, so the treatment method has the economic advantage of low treatment cost.

However, in the conventional artificial wetland, a water level control device is not provided, and only when the water level entering the wetland is at a full water level, the effluent overflows, so that the regulation of the wetland water quantity and the hydraulic retention time is lack of control. In addition, in drought seasons, due to the fact that rainfall is less, water in the wetland is in a slow-delay state, and the water quality purification function of the wetland is weakened. If continuous rainfall occurs, the wetland is lack of the regulation and storage function, and the purpose of treating pollutants cannot be achieved. In addition, when rainwater carries non-point source pollutants into the wetland, a large amount of suspended substances are usually contained, and inevitably block a filter layer in a short time, so that the treatment efficiency of the wetland is reduced.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a high-efficiency composite wetland system for reducing rainfall runoff pollutants, which solves the problems of poor decontamination effect and low decontamination efficiency of the conventional artificial wetland due to no water level control function.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

the efficient compound wetland system for reducing rainfall runoff pollutants comprises a surface flow wetland connected with a river, wherein a water level control device is arranged at a water inlet of the surface flow wetland; a sedimentation area is arranged between the surface flow wetland and the water level control device, a deep purification unit for reducing pollutants in water is arranged at a water outlet of the surface flow wetland, rainwater in the surface flow wetland enters the deep purification unit through the flow guide device, and the deep purification unit is communicated with a water collecting well with a water outlet;

the deep purification unit comprises an impermeable layer and a filter material layer arranged below the impermeable layer and used for filtering rainwater; the impermeable layer is provided with a water guide pipe for guiding rainwater into the filter material layer, and an oxygenation device is arranged in the water guide pipe; be provided with phosphorus removal device on the barrier layer, phosphorus removal device is provided with a plurality of holes of permeating water that communicate with the precoat layer including the dephosphorization urceolus that runs through barrier layer and precoat layer on the dephosphorization urceolus, and the top of dephosphorization urceolus is higher than aqueduct top height, and the bottom and the sump pit intercommunication of dephosphorization urceolus.

Further, the filter material layer comprises an upper filter material layer for supporting the impermeable layer and a lower filter material layer for filtering ammonia nitrogen substances in the rainwater; gravels with the diameter of 5 mm-10 mm are uniformly filled in the upper filter material layer, and the thickness of the upper filter material layer is 100 mm-200 mm; porous zeolite, volcanic rock and limestone with the mass ratio of 1:1:1 are uniformly filled in the lower filter material layer, and the thickness of the lower filter material layer is 1500-2000 mm.

Furthermore, a phosphorus removal inner cylinder which is equal to the phosphorus removal outer cylinder in height and penetrates through the impermeable layer and the filter material layer is arranged in the phosphorus removal outer cylinder, a detachable phosphorus removal filler block is arranged between the phosphorus removal outer cylinder and the phosphorus removal inner cylinder, the phosphorus removal filler block is formed by uniformly mixing and sintering coal ash, clay and an caking agent in a mass ratio of 7:2:1 to form a porous block structure, a plurality of water permeable holes communicated with the filter material layer are uniformly formed in the circumferential outer wall of the phosphorus removal inner cylinder, and the bottom of the phosphorus removal outer cylinder and the bottom of the phosphorus removal inner cylinder are communicated with the bottom of the water collecting well through a water drainage pipe.

Further, the water level control device comprises a water inlet gate and a flow liquid level sensor for detecting the water level height in the surface flow wetland.

Further, the depth of the precipitation zone is 90 cm-150 cm.

Furthermore, the surface flow wetland comprises a shallow water area and a deep water area which are communicated with each other, submerged plants are planted at the bottoms of the shallow water area and the deep water area, and the shallow water area is communicated with the settling area.

Furthermore, the guiding device comprises a guiding gutter for guiding rainwater in the shallow water area into the upper surface of the impermeable layer, the end part of the guiding gutter connected with the shallow water area is of a horizontal structure, the bottom of a horizontal pipe section of the guiding gutter is flush with the water surface of the shallow water area, and a filter screen is arranged on the horizontal pipe section.

Further, the oxygenation device comprises a rotating rod which is rotatably arranged in the water guide pipe, and a plurality of blades are arranged on the circumferential outer wall of the rotating rod.

Furthermore, the water outlet is positioned at the middle upper part of the water collecting well, and a water gate for adjusting the liquid level height of the water collecting well is arranged at the water outlet.

Furthermore, the top of the water guide pipe and the top of the dephosphorization outer barrel are both provided with a filter cover.

An efficient compound wetland system for reducing rainfall runoff pollutants is formed near a river, the river is communicated with a precipitation area at the front end of the wetland through a gate which is arranged at a water inlet and controlled by a water level sensor, the rainfall runoff flows from a low water level to a preset water level, and the precipitation area is formed at the upstream and precipitates impurities such as floaters, suspended matters and the like in the rainfall runoff. The purified rainwater is guided to the surface flow wetland in the middle section for reducing pollutants in water, and meanwhile, a certain landscape water surface is formed through the winding design of landform. Rainwater is guided into the deep purification unit at the tail end of the surface flow wetland through the flow guide device, and nitrogen and phosphorus pollutants in the rainwater are further removed through the filtering layer and the phosphorus removal device in the deep purification unit, so that the risk of water body outbreak eutrophication is reduced. The dephosphorization filler block is in a modular design, and can be quickly and conveniently replaced along with the saturation of the adsorption material. And finally, arranging a liquid level control device at the outlet end of the water collecting well, and effectively controlling the water surface height of the wetland through the front and rear sections of the liquid level control devices.

The invention has the beneficial effects that:

1. the efficient composite wetland system for reducing rainfall runoff pollutants in the scheme can effectively control non-point source pollutants carried by the rainfall runoff. By arranging the settling zone, inorganic particulate matters in rainwater can be reduced, the blockage of the wetland system is reduced, and the service life of the wetland system is prolonged.

2. The surface flow wetland and the terminal deep purification unit formed in the middle section of the wetland system in the scheme can effectively remove organic pollutants and nitrogen and phosphorus nutrients in rainwater, reduce the risk of water bloom outbreak, and the dephosphorization filler block adopts a modular design, so that the installation and the replacement of materials are convenient.

3. The invention can lead rainfall runoff to stay in the surface flow wetland for a long time through the water level control device at the water inlet of the surface flow wetland and the water gate at the water outlet so as to achieve the purpose of fully purifying the rainwater, and can adjust the water level of the wetland system according to the requirement, and simultaneously, a certain landscape water surface is formed during water purification, thereby increasing the hydrophilicity of residents and beautifying the surrounding environment.

Drawings

Fig. 1 is a schematic plan view of the high-efficiency complex wetland system for reducing rainfall runoff pollutants according to the invention.

Fig. 2 is a side view structural view of the highly efficient complex wetland system for reducing rainfall runoff pollutants of the present invention.

FIG. 3 is a schematic structural diagram of a deep purification unit.

FIG. 4 is a schematic top view of a phosphorus removal device.

Fig. 5 is an enlarged structure schematic diagram of the phosphorus removal filler block.

Fig. 6 is an enlarged cross-sectional view of a portion a in fig. 3.

Fig. 7 is an enlarged sectional view schematically illustrating a structure at B in fig. 3.

Wherein, 1, a precipitation zone; 2. surface flow wetland; 3. a flow guide device; 4. a deep purification unit; 5. a water collecting well; 6. a flow level sensor; 7. a water inlet gate; 8. a water inlet; 9. a shallow water region; 10. a deepwater zone; 11. submerged plants; 12. a water conduit; 13. a water outlet; 14. modeling the wetland landscape; 15. a drain pipe; 16. filtering with a screen; 17. a diversion trench; 18. a filter material layer; 19. an impermeable layer; 20. a filter material layer is arranged; 21. a lower filter material layer; 22. a phosphorus removal device; 23. a dephosphorization outer cylinder; 24. a dephosphorization inner barrel; 25. a phosphorus removal filler block; 26. an oxygenating device; 27. rotating the rod; 28. a blade.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention as defined and defined in the appended claims, and all matters produced by the invention using the inventive concept are protected.

As shown in fig. 1 to 7, the invention provides an efficient composite wetland system for reducing rainfall runoff pollutants, which comprises a surface flow wetland 2 connected with a river, wherein a water level control device is arranged at a water inlet 8 of the surface flow wetland 2; a sedimentation region 1 is arranged between the surface flow wetland 2 and the water level control device, a deep purification unit 4 for reducing pollutants in water is arranged at a water outlet of the surface flow wetland 2, rainwater in the surface flow wetland 2 enters the deep purification unit 4 through a flow guide device 3, and a water collecting well 5 with a water outlet 13 is communicated with the deep purification unit 4; the water outlet 13 is positioned at the middle upper part of the water collecting well 5, and a water gate for adjusting the liquid level of the water collecting well 5 is arranged at the water outlet 13.

The deep purification unit 4 comprises an impermeable layer 19 and a filter material layer 18 which is arranged below the impermeable layer 19 and used for filtering rainwater; an aqueduct 12 for guiding rainwater into the filter material layer 18 is arranged on the impermeable layer 19, and an oxygenation device 26 is arranged in the aqueduct 12; be provided with phosphorus removal device 22 on the barrier layer 19, phosphorus removal device 22 is including the dephosphorization urceolus 23 that runs through barrier layer 19 and precoat 18, is provided with a plurality of holes of permeating water that communicate with the precoat 18 on the dephosphorization urceolus 23, and the top of dephosphorization urceolus 23 is higher than aqueduct 12 top height, and the bottom and the sump pit 5 of dephosphorization urceolus 23 communicate. So that the rainwater can only enter from the water guide pipe 12 and enter the dephosphorization device 22 after flowing through the filter material layer 18.

The water level control device comprises a water inlet gate 7 and a flow liquid level sensor 6 for detecting the water level height in the surface flow wetland 2. The inflow gate 7 is controlled by the flow level sensor 6, rainwater enters the surface wetland 2 through the inflow port 8 to form an upstream, and the depth of the sedimentation zone 1 is preferably formed to a depth of 90cm to 150cm to sediment inorganic particulate matter, so that the cleaning can be easily performed, and the cleaning work is not frequently performed with the accumulation of time. On the other hand, the water inlet gate 7 ascends and descends and is arranged on the water inlet 8, and the matched flow liquid level sensor 6 drives the motor or the hydraulic unit to control the opening and closing height of the water gate according to the quantity of the rainwater and the set hydraulic retention time.

The surface flow wetland 2 is arranged between the settling zone and the deep purification unit 4, the surface flow wetland 2 comprises a shallow water zone 9 and a deep water zone 10 which are communicated with each other, submerged plants 11 are planted at the bottoms of the shallow water zone 9 and the deep water zone 10, and the shallow water zone 9 is communicated with the settling zone 1. The submerged plant 11 can fully utilize solar energy to carry out photosynthesis to decompose organic pollutants affluxed by rainfall runoff, and the rainwater in the deep water area 10 at the tail end of the surface flow wetland 2 is purified and then enters the deep purification unit 4 at the rear section through the flow guide device 3.

The middle section of the surface flow wetland 2 is provided with a wetland landscape modeling 14 in a winding and tortuous three-dimensional structure, so that the whole wetland system is beautified.

As shown in fig. 3, the diversion device 3 includes a diversion trench 17 for guiding rainwater in the shallow water region 9 into the upper surface of the impermeable layer 19, the end of the diversion trench 17 connected with the shallow water region 9 is in a horizontal structure, the bottom of the horizontal pipe section of the diversion trench 17 is flush with the water surface of the shallow water region 9, and the horizontal pipe section is provided with a filter screen 16. The rainwater that purifies is collected through the mode of overflow in deep water district 10, and when the liquid level height in deep water district 10 was higher than the horizontal pipeline section of guiding gutter 17, the rainwater in deep water district 10 passes through guiding gutter 17 and gets into in the deep purification unit 4, and filter screen 16 can block that the floater passes through guiding gutter 17 and gets into in the deep purification unit 4.

As shown in fig. 3 to 7, the impermeable layer 19 in the deep purification unit 4 accumulates rainwater, the rainwater flows on the surface of the impermeable layer 19, the impermeable layer 19 can be implemented by a bentonite waterproof blanket or clay tamping, etc., so that the rainwater on the impermeable layer 19 passes through the filter material layer 18 through the water conduit 12 and finally flows into the phosphorus removal device 22, the thickness of the impermeable layer 19 is preferably 100mm to 200mm, the waterproof performance is excellent, rainwater infiltration is avoided, and the decontamination effect of the rainwater is reduced.

The filter material layer 18 comprises an upper filter material layer 20 for supporting the impermeable layer 19 and a lower filter material layer 21 for filtering ammonia nitrogen substances in rainwater; gravels with the diameter of 5 mm-10 mm are uniformly filled in the upper filter material layer 20, the thickness of the upper filter material layer 20 is 100 mm-200 mm, and the upper filter material layer 20 mainly plays a role in supporting the impermeable layer 19 to prevent the impermeable layer 19 from collapsing; porous zeolite, volcanic rock and limestone with the mass ratio of 1:1:1 are uniformly filled in the lower filter material layer, the thickness of the lower filter material layer is 1500-2000 mm, rainwater stably passes through the filter material layer 18, a small amount of organic pollutants and ammonia nitrogen pollutants contained in the rainwater are intercepted by the filter material layer 18, so that a biological film formed on the filter material layer 18, and the organic pollutants and the ammonia nitrogen pollutants are degraded and converted by microorganisms attached to the filter material layer 18.

The top of the water guide pipe 12 is provided with a filtering cover for blocking the drift flow from flowing into the water guide pipe, the inside of the water guide pipe 12 is provided with an oxygenation device 26 comprising a rotating rod 27 rotatably arranged in the water guide pipe 12, and the circumferential outer wall of the rotating rod 27 is provided with a plurality of blades 28. The water introduction tube 12 may be a hollow tube having a circular or polygonal cross section, and the rotation rod 27 has one end fixed to the upper cover and the other end fixedly mounted to a bearing at the center of the bottom surface. The blades 28 rotate in accordance with the direction of the falling water flow, so that the external air is wrapped into the water flow and enters the filter material layer 18, a certain aeration and oxygenation effect is achieved, the activity of microorganisms in the biological membrane is improved, and the decontamination efficiency is further improved.

The dephosphorization device 22 comprises a dephosphorization outer cylinder 23 and a dephosphorization inner cylinder 24 which both penetrate through the impervious layer 19 and the filter material layer 18, a detachable dephosphorization filler block 25 is arranged between the dephosphorization inner cylinder 24 and the dephosphorization inner cylinder 24, the dephosphorization filler block 25 is a porous block structure formed by uniformly mixing and sintering fly ash, clay and caking agent with the mass ratio of 7:2:1, a plurality of water-permeable holes communicated with the filter material layer 18 are uniformly arranged on the circumferential outer walls of the dephosphorization outer cylinder 23 and the dephosphorization inner cylinder 24, and the bottom of the dephosphorization outer cylinder 23 and the bottom of the dephosphorization inner cylinder 24 are communicated with the bottom of the water collecting well 5 through a drain pipe 15.

The dephosphorization filler block 25 is made into a ladder shape according to the shapes of the dephosphorization outer cylinder 23 and the dephosphorization inner cylinder 24 so as to be convenient to arrange and replace, the dephosphorization outer cylinder 23 is connected with the filter material layer 18 and is 30-50 cm higher than the top of the impermeable layer 19, the contact part of the dephosphorization outer cylinder 23 and the anti-deep layer is sealed and is subjected to impermeable treatment at the joint part so as to prevent short flow of water, the contact part of the dephosphorization outer cylinder 23 and the filter material layer 18 is uniformly distributed with permeable holes with the diameter of 5-10 mm so as to lead rainwater to flow in, the height of the dephosphorization inner cylinder 24 is the same as that of the dephosphorization outer cylinder 23, the inner wall is also provided with permeable holes with the diameter of 5-10 mm, in addition, the top end of the dephosphorization outer cylinder 23 is provided with a filter cover so as to prevent sundries from entering. Rainwater passing through the filter material layer 18 enters the interior of the phosphorus removal device 22 through the water permeable holes and flows through the phosphorus removal filler blocks 25, and after the phosphorus in the rainwater is absorbed by the phosphorus removal filler blocks 25, the rainwater enters the water collecting well 5 through the bottom water drainage pipe 15 and is finally discharged.

In the water collecting well 5, a water outlet 13 is positioned at the middle upper part of the water collecting well 5, and a water gate for adjusting the liquid level of the water collecting well 5 is arranged at the water outlet 13. The bottom parts of the dephosphorization outer cylinder 23 and the dephosphorization inner cylinder 24 are communicated with the bottom part of the water collecting well 5 through a water discharge pipe 15, a water gate for adjusting the liquid level height is arranged on the water discharge port 13, when the gate is placed at the bottom end, the surface flow wetland 2 is in a low water level state, and when the gate is placed at the top end, the surface flow wetland 2 is in a high water level state; the height of the water gate is adjusted to control the hydraulic retention time of the rainwater in the wetland system. After the rainwater stops, the rainwater can also be used for controlling the liquid level height of the wetland system. Can make the rainwater stay for a long time in the wetland system and form a certain landscape water surface.

The working process of the efficient composite wetland system for reducing the rainwater runoff pollutants comprises the following steps: when the treated rainwater runoff water is used, rainwater runoff flows into the surface flow wetland 2 through the open water inlet 8. When the rainfall runoff water level is gradually increased, after the flow water level detection sensor detects a corresponding rainfall value, the inlet gate 7 is opened to enable rainwater to enter the wetland system, the rainwater firstly enters the precipitation zone 1 of the wetland system, and particulate matters such as silt and the like wrapped by the rainwater are precipitated. Then the rainwater enters the surface flow wetland 2, and organic pollutants in the water are firstly removed through the hydraulic regulation function brought by the curved and fluctuant structure of the wetland and the purification function of the submerged plants 11. Then, the rainwater enters the deep purification unit 4 through the diversion device 3, and the rainwater enters the filter material layer 18 through the diversion pipe. At this time, the content of dissolved oxygen in the rainwater is increased through the action of the rotating blades 28 in the draft tube and the falling process of the water drop, so that the aerobic state of the filter material system is maintained. The oxygenated rainwater flows in the filter material layer 18, and ammonia nitrogen substances in the rainwater are removed through the adsorption effect of the filter material in the lower filter material layer 21 and a biological membrane formed on the filter material. Then the flowing rainwater passes through the dephosphorization outer cylinder 23 and enters the dephosphorization device 22, after the phosphorus in the water is adsorbed by the dephosphorization filler, the rainwater flows through the drainage pipe 15 at the bottom of the dephosphorization device 22 through the dephosphorization inner cylinder 24 and flows into the water collecting well 5, and finally the rainwater is discharged through the drainage port 13 by opening the water gate capable of adjusting the liquid level. Under the normal design condition, the rainfall runoff can stay for 24-48 hours in the wetland system, so that enough stay time is provided for removing pollutants brought along with the rainfall runoff.

Claims

1. The efficient composite wetland system for reducing rainfall runoff pollutants is characterized by comprising a surface flow wetland (2) connected with a river, wherein a water level control device is arranged at a water inlet (8) of the surface flow wetland (2); a sedimentation area (1) is arranged between the surface flow wetland (2) and the water level control device, a deep purification unit (4) for reducing pollutants in water is arranged at a water outlet of the surface flow wetland (2), rainwater in the surface flow wetland (2) enters the deep purification unit (4) through the flow guide device (3), and the deep purification unit (4) is communicated with a water collecting well (5) with a water outlet (13);

the deep purification unit (4) comprises an impermeable layer (19) and a filter material layer (18) which is arranged below the impermeable layer (19) and used for filtering rainwater; a water guide pipe (12) for guiding rainwater into the filter material layer (18) is arranged on the impermeable layer (19), and an oxygenation device (26) is arranged in the water guide pipe (12); a phosphorus removal device (22) is arranged on the impermeable layer (19), the phosphorus removal device (22) comprises a phosphorus removal outer cylinder (23) which penetrates through the impermeable layer (19) and the filter material layer (18), a plurality of water permeable holes communicated with the filter material layer (18) are formed in the phosphorus removal outer cylinder (23), the top of the phosphorus removal outer cylinder (23) is higher than the top of the water guide pipe (12), and the bottom of the phosphorus removal outer cylinder (23) is communicated with the water collecting well (5);

the filter material layer (18) comprises an upper filter material layer (20) for supporting the impermeable layer (19) and a lower filter material layer (21) for filtering ammonia nitrogen substances in rainwater; gravels with the diameter of 5 mm-10 mm are uniformly filled in the upper filter material layer (20), and the thickness of the upper filter material layer (20) is 100 mm-200 mm; porous zeolite, volcanic rock and limestone with the mass ratio of 1:1:1 are uniformly filled in the lower filter material layer, and the thickness of the lower filter material layer is 1500-2000 mm;

the dephosphorization outer barrel (23) is internally provided with a dephosphorization inner barrel (24) which has the same height as the dephosphorization outer barrel and penetrates through the impermeable layer (19) and the filter material layer (18), a detachable dephosphorization filler block (25) is arranged between the dephosphorization outer barrel (23) and the dephosphorization inner barrel (24), the dephosphorization filler block (25) is formed by uniformly mixing and sintering coal ash, clay and caking agent in a mass ratio of 7:2:1 to form a porous block structure, a plurality of water-permeable holes communicated with the filter material layer (18) are uniformly arranged on the circumferential outer wall of the dephosphorization inner barrel (24), and the bottom of the dephosphorization outer barrel (23) and the bottom of the dephosphorization inner barrel (24) are communicated with the bottom of the water collecting well (5) through a drain pipe (15).

2. The high-efficiency compound wetland system for reducing rainfall runoff pollutants according to claim 1, wherein the water level control device comprises a water inlet gate (7) and a flow liquid level sensor (6) for detecting the water level in the surface flow wetland (2).

3. The high efficiency complex wetland system for reducing rainfall runoff contaminants of claim 1 wherein the depth of the settling zone (1) is between 90cm and 150 cm.

4. The high-efficiency compound wetland system for reducing rainfall runoff pollutants according to claim 2, characterized in that the surface flow wetland (2) comprises a shallow water area (9) and a deep water area (10) which are communicated with each other, submerged plants (11) are planted at the bottoms of the shallow water area (9) and the deep water area (10), and the shallow water area (9) is communicated with the settling area (1).

5. The high-efficiency compound wetland system for reducing rainfall runoff pollutants according to claim 4, wherein the diversion device (3) comprises a diversion trench (17) for guiding rainwater in the shallow water area (9) into the upper surface of the impermeable layer (19), the end part of the diversion trench (17) connected with the shallow water area (9) is of a horizontal structure, the bottom of a horizontal pipe section of the diversion trench (17) is flush with the water surface of the shallow water area (9), and a filter screen (16) is arranged on the horizontal pipe section.

6. The high efficiency complex wetland system for reducing rainfall runoff contaminants of claim 1, wherein the oxygenation device (26) comprises a rotating rod (27) rotatably disposed within the water conduit (12), the rotating rod (27) having a plurality of blades (28) disposed on an outer circumferential wall thereof.

7. The high-efficiency compound wetland system for reducing rainfall runoff pollutants according to claim 1, wherein the water discharge opening (13) is positioned at the middle upper part of the water collecting well (5), and a water gate for adjusting the liquid level of the water collecting well (5) is arranged at the water discharge opening (13).

8. The high-efficiency compound wetland system for reducing rainfall runoff pollutants according to any one of claims 1 to 7, wherein the top of the water guide pipe (12) and the top of the phosphorus removal outer cylinder (23) are both provided with a filter cover.